when the starter button is pressed the relay is energized by "A" and "B" and a connection is made from "F" to "C" this powers the coil 1 "C" to "D" and powers coil 2 "C" to "E+G", because the starter motor is not turning at this point "G" is grounded through the armature of the starter motor, so both coils are powered and this pulls the rod into the solenoid and engages the drive gear with the flywheel also connecting "F" to "G" and powering the starter motor so it turns. Now because connection "G" is powered coil 2 has the same voltage both sides of it so it does not work or pull a high load, as the starter gear is already engaged and the motor is cranking the engine, the solenoid is only using coil 1 to hold it in position, once engine has started and starter button released this cuts the power to "C" and the coil 1 is de-energized so releasing the drive gear from the flywheel and stopping starter motor turning.
Now the engine is running all is good, but what happens if you push the clutch pedal down too far and it presses the starter button ? Answer nothing, this is because now the generator is producing power and connection "A" is no longer grounded through the generator the relay will not work to energize the starter !!!
